Tubing coupling

ABSTRACT

A coupling of either fixed or flexible structure for removably connecting the adjacent generally axially aligned ends of two lengths of tubing. The coupling whether of fixed or flexible structure includes a resilient tubular connector that effects primary surface to surface seals with flared end portions of said tubing, and secondary seals by resilient rings that pressure contact said flared end portions, said connector, and ferrules that form a part of said coupling. Flexible cable or marcelled high-tensile strength wire removably engage slotted portions of the ferrules to prevent longitudinal separation thereof, and without axially loading the connector beyond that degree required to maintain said surface to surface seals.

United States Patent Burtis Mar. 7, 1972 [541 TUBING COUPLING FORElGN PATENTS OR APPLICATIONS Inventor: Wilson Burtis, te Calif. 686,387 Great Britain ..285/109 73 DeLl Tu bin Call! rnla Inc. P l 1 Assume ceton r i u. r e o "n Primary Examiner-David J.Wil1iamowsky Assistant Examiner-Wayne L. Shedd [22] filed: Jae 1970 Attomey-William C. Babcock [21) Appl.No.: 2470 57] ABSTRACT (52] U.S.Cl. ..285/1l4, 285/227, 285/301 A coupl ng of either fixed or flexible structure for removably [5]] In. (I F16|13/04 connecting the adjacent generally axially aligned ends of two '[58] fleldofsearch ..285/l14, 227, 229, 301, 126, lengths of tubing. The coupling whether of fixed or flexible 285/382.4, 364, 406, 109, 299, 300, 371, 398, structure includes a resilient tubular connector that effects 3345 primary surface to surface seals with flared end portions of said tubing, and secondary seals by resilient rings that pressure Rdemms Cited contact said flared end portions, said connector, and ferrules that form a part of said coupling. Flexible cable or marcelled UNITED STATES PATENTS high-tensile strength wire removably engage slotted portions 428,186 5/1890 Vering ..285/301 of the ferrules to prevent longitudinal separation thereof. and 2,158,620 1939 Easfman X without axially loading the connector beyond that degree 2,793-833 1957 a required to maintain said surface to surface seals. 2,898,940 8/1959 Cole .285/301 X 3,084,957 4/1963 Caldwell ..285/30l X iPrawingi igures 4 PAIENTEBHAR 1 m2 7 3, 647, 246

sum 1 or 2 "Es-zil- INVENTOR. W/wo/v A Bue 77s ATTORNEV TUBING COUPLING BACKGROUND OF THE INVENTION 1. Field of the Invention Tubing coupling and tubing flaring tool for use therewith.

2. Description of the Prior Art The effective connecting of fluid-carrying lines that may be misaligned and subject to substantial temperature variations has in the past presented a severe problem for which no truly satisfactory solution had been achieved prior to the present invention. The present invention provides a coupling that may be used to removably connect the adjacent end portions of two lengths of tubing that may be misaligned and subject to longitudinal movement due to temperature variations and overcomes the operation deficiencies of prior art devices used for this purpose.

SUMMARY OF THE INVENTION A coupling of either fixed or flexible structure that includes two ferrules and a resilient tubular connector. The ferrules are secured to the adjacent end portions of two lengths of tubing, with the connector extending between the ferrules and effecting primary surface seals with said end portions. Two resilient rings are operatively associated with said ferrules, connector, and end portions of said tubing in such a manneras to effect secondary seals therewith. The ferrules are slotted and removably engaged by a pliable cable or marcelled high tensile strength wire to prevent longitudinal separation of the ferrules when the coupling is subjected to high internal pressure, with resultant breaking of the primary seals.

A major object of the present invention is to provide a tubing coupling that includes two ferrules and a resilient connector extending therebetween, with cable or a marcelled wire engaging the ferrules to prevent inadvertent separation thereof, and without the cable or wire structurally stressing the connector beyond that degree required to effect said primary surface to surface seals.

Another object of the invention is to supply a coupling that may be used to maintain nonleaking communication between the adjacent ends of two lengths of tubing that may be misaligned or subject to longitudinal or angular movement relative to one another, and the coupling capable of being mounted on the tubing without tools and by persons having little or no specialized knowledge of the coupling art.

A further object of the invention is to furnish a coupling that will fail safe even though the marcelled wire or pliable cable connecting the ferrules should break.

Yet another object of the invention is to supply a tubing coupling in which the surface to surface seals remain in a static sealing position even though there may be substantial flexing or longitudinal deformation of the connector extending between the ferrules.

A further object of the invention is to provide a coupling that effectively maintains nonleaking communication between the end portions of the lengths of tubing with which it is associated, even though the primary surface to surface seals of the coupling fail.

A still further object of the invention is to provide a coupling in which the'cable lacing thereon is self adjusting and results in symmetrical loading of the ferrules to assure maximum sealing conditions between the coupling and end portions of the tubing with which it is associated.

Another object of the invention is to provide a tool for easily and conveniently flaring an end portion of a length of tubing after a ferrule has been mounted on said end portion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a first form of a coupling of flexible structure connecting two axially aligned lengths of tubing;

FIG. 2 is a top plan view of the first form of coupling shown in FIG. 1;

FIG. 3 is a transverse cross-sectional view of the first form of coupling taken on the line 3-3 of FIG. l;

FIG. 4 is a longitudinal cross-sectional view of the first form of coupling taken on the line 4-4 of FIG. 2;

FIG. 5 is a fragmentary enlarged longitudinal cross-sectional view of one of the ferrules and bellows used in the first form of the coupling and illustrating an alternate form of sealing ring;

FIG. 6 is a front elevational view of the portion of the ferrule shown in FIG. 5, and taken on the line 6-6 thereof;

FIG. 7 is a side elevational view of a second form of coupling of rigid structure connecting the adjacent end portions of two lengths of tubing;

FIG. 8 is a longitudinal cross-sectional view of the second form of coupling taken on the line 88 of FIG. 7;

FIG. 9 is a side elevational view of an end portion of marcelled wire used in holding the ferrules of the second form of coupling together as shown in FIGS. 7 and 8;

FIG. 10 is a perspective view of an endless plastic covered cable loop used in maintaining the marcelled wire in a ferrule engaging position as shown in FIG. 7;

FIG. 11 is a longitudinal cross-sectional view of a section of the cable shown in FIG. 10 and taken on the line II II thereof;

FIG. 12 is a longitudinal cross-sectional view of a third form of the coupling;

FIG. 13 is a side elevational view of a tool for forming an end portion of tubing into a flare that interlocks with one of said ferrules; and

FIG. 14 is a front elevational view of the tool shown in FIG. 13 taken on the line l4l4 thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first form A of the coupling as may best be seen in FIGS. 1 to 4 is adapted to establish a flexible connection between adjacently disposed ends of first and second lengths of tubing B. The first form A of the coupling includes first and second ferrules C that interlock with circumferentially extending first and second flares 16 formed on the adjacent ends of the first and second lengths of tubing B by use of the tool D shown in FIGS. 13 and 14.

A tubular connector E in the form of a resilient bellows extends between first and second ferrules C and effects primary metal to metal seals with first and second flares 16 as may be seen in detail in FIGS. 4 and 5. First and second ferrules C have resilient sealing rings 18 associated therewith that effect secondary seals between the connector E, the flares I6, and the ferrules. An alternate form of sealing ring 18' is illustrated in FIG. 5 that has a transverse cross section that defines three lobes. Connector E is formed from a resilient sheet material and may flex both longitudinally and transversely to permit limited movement of the first and second lengths of tubing relative to one another. The first and second ferrules C in the first form A of the coupling are removably connected by a pliable cable F as shown in FIG. 1 to prevent inadvertent longitudinal separation of the ferrules, as well as to maintain a desired pressure contact at the primary seals.

Each of the ferrules C is defined by a ring shaped rigid body 20 that has a bore 22 extending longitudinally therethrough. Said 22 bore is of such diameter as to slidably and snugly engage the exterior surface of one of the lengths of tubing. Each body 20 has a circumferentially extending first recess 24 therein that extends outwardly from bore 22.

Each flare 16 is defined by a first circumferential section 16a of the tubing that extends forwardly and outwardly and develops into a second section 16b that is substantially parallel to the nonflared portion of a length of tubing B. Each flare l6 defines a circumferentially extending, interior, longitudinally curved surface 26 the purpose of which will later be explained. Each recess 24 is of such shape as to substantially engage the entire exterior surface of one of the flares I6, when the flare is formed therein by the use of the tool D shown in FIGS. I3 and 14.

Connector E, as may best be seen. in FIG. 4, includes two circular end sections 28 that have ring shaped walls 30 that taper towards one another at a slight angle. Connector E between end sections 28 is in the form of a bellows 32 which on its ends is sealingly connected to the end sections 28 by conventional means such as soldering, brazing, welding or the like (not shown). Walls 30 have cylindrical shells 34 of substantially lesser diameter projecting outwardly therefrom. The shells 34 terminate in circumferentially inwardly extending, curved extremities 36 that pressure contact the surfaces 26 to effect metal to metal primary seals therewith. End sections 28 are disposed in circumferentially extending second recesses 38 formed in the adjacent end surfaces 40 of ferrules C.

The ferrules C as shown in FIG. I have a number of angularly disposed, circumferentially spaced slots 42 therein that are engaged by an endless loop of pliable cable 44, which loop is shown in FIG. 11a. The cable 44 is laced into the slots 42 in a crisscross pattern and defines a sequence of figure 8s as the cable extends around the ferrules C. The cable 44 is tensioned sufficiently to maintain surfaces 26 and end extremities 36 in desired pressure contact to effect said primary surface to surface seals. In FIG. 4 it will be noted that walls 30 are outwardly disposed in the second recesses 38 to assure surfaces 26 and end extremities 36 being in pressure sealing contact when the cable 44 is tensioned. The bellows 32 of connector C may be of two-ply construction as shown in FIG. if desired. Inadvertent displacement of the cable 44 from slots 42 and ferrules C from connector E is prevented by notched resilient rings 46 as shown in FIG. 5 that engage the exterior circumferential surfaces 48 of the ferrules and extend into circumferential grooves 50 formed therein. Rings 46 extend inwardly over end surfaces 40 of the ferrules C and surfaces 32a of bellows.

Uniform tension may be maintained on cable 44 by causing a loop 44a thereof to removably engage a slotted block 52 that is slidably mounted on a threaded rod 54 that extends outwardly from second ferrule C as shown in FIG. 2. A compressed helical spring 56 encircles rod 54 and has the abutting ends thereof in contact with second ferrule C and block 52. Rod 54 is engaged by a nut 58 that adjustably limits the outward positioning of block 52 relative to second ferrule C. By adjusting nut 58 on rod 54 the tension on cable 44 may be increased or decreased, and the pressure sealing contact between surfaces 26 and end extremities 36 controlled. The resilient rings 18 are in sealing engagement with the external surfaces of shells 34, flares l6, and ferrules C as shown in FIG. 4 and effect secondary seals between connector E and first and second lengths of tubing B.

The resilient sealing ring 18 may be of either the circular transverse cross section shown in FIG. 5 or the three lobe cross section illustrated in FIG. 12. A sealing ring of the last mentioned transverse cross section is identified by the numeral 18'. Cable 44 as shown in FIG. 11 is formed from a number of strands 44a of a material having a high tensile strength, and the strands being enveloped by a plastic sheath 44b, when the cable 44 is to be used on a coupling A that is subjected to high-temperature conditions, the cable is preferably impregnated with molybdenum disulfide. The coupling A above described has been found to successfully maintain a seal with i axial misalignment and l inch axially travel.

The first and second ferrules C when mounted on the adjacent ends of first and second lengths of tubing B as previously described may be used to partially define a second form of coupling A that is of rigid structure. In the second form of coupling A as illustrated in FIGS. 7 and 8 the ferrules C have the end surfaces 40 held in abutting contact by a band of marcelled wire 60 of high tensile strength that engages the slots 42. Wire 60 is locked in slots 42 by the snap rings 62 that removably engage the circumferential grooves 50 formed on the exterior surfaces of the ferrules C.

The second form of coupling A includes a connector E that has two longitudinally spaced tubular shells 34' which on their adjacent ends are connected by an outwardly bowed tubular segment 64 that is longitudinally deformed in a direction to force end extremities 36 into pressure sealing contact with surfaces 26. The outwardly bowed segment 64 extends into an annulus-shaped space in the interior of the ferrules C that is defined by the two second recesses 38. Resilient rings 18 engage the shells 34 and cooperate with the flares l6 and forrules C to provide secondary seals in the same manner as in the first form A of the coupling. Second form A of the coupling operates in the same manner as the first form A, but with the exception that the second form permits no longitudinal or transverse movement of the two lengths of tubing B relative to one another.

A third form A" of the coupling is shown in FIG. 12 in which the first and second ferrules C have tubular extensions 66 projecting therefrom that are welded or brazed to ends 68 of the two lengths of tubing B. The ferrules C have the end surfaces 40 held in abutting contact in the third form of coupling A" in the same manner as described in the second form A.

A tubular connector G is provided for the third form A of the coupling. Connector G includes two longitudinally spaced cylindrical shells 70 that on their outer ends develop into inwardly curved extremities 72 that are in pressure sealing contact with circumferential longitudinally curved surfaces 74 defined in the interior of the ferrules C as shown in FIG. 12.

The adjacent ends of the shells 70 develop into an outwardly projecting portion 76 that is longitudinally stressed to force end extremities 72 into pressure sealing contact with surfaces 74. Outwardly projecting portion 76 in transverse cross section is defined by two L-shaped segments 78 that are connected on their adjacent ends by an inwardly extending loop 80. Sealing rings 18' are disposed in first recesses 24 as may be seen in FIG. 12 and pressure contact shells 70 and ferrules C to provide secondary seals in the third form A" of the coupling. The wire 60 is used in the third form A" of the coupling to hold the ferrules C together in abutting relationship as described in connection with the second form A.

The too] D shown in FIGS. 13 and 14 is used to form a flare 16 on an end portion of a length of tubing B after a ferrule C has been mounted on said end portion. A first circular die 78 is slidably mounted on tubing B and moved to a position adjacent to an end thereof. A second circular die 80 interlocks with the first die 78. The dies 78 and 80 grip a ferrule C therebetween. Second die 80 has a stop 82 thereon that is contacted by the end of tubing B that is adjacent to the circum ferential segment thereof that is to be formed into the flare 16. By use of the stop 82, a circumferential segment of the tubing B of the correct length to form the flare I6 is disposed in radial alignment with first recess 24.

Tool D includes an elongate body 84 that rotatably supports a first flare forming roller 86 and second roller 88 in fixed longitudinal spacing. Roller 86 has an external surface of the same configuration as the interior surface of flare 16. First roller 86 engages the interior surface of an end section of tubing B, and second roller 88 engages the end surface 40 of ferrule B.

Two spaced spools 90 rotatably engage the exterior surfaces of first and second dies 78 and 80 and serve to removably hold them together in interlocking relationship. Spools 90 are rotatably supported on the lower end of a rigid body 92. The body 92 and spools 90 are longitudinally movable relative to body 84.

The body 84 includes a forwardly extending portion 94 in which a tapped bore (not shown) is formed that is engaged by a threaded rod 96. One endof rod 96 is journaled in body 92, and the other end of the rod supports a handle 98. When rod 96 is rotated in an appropriate direction the distance between rollers 86 and 88, and the spools 90 is shortened, with first roller 84 forcing an end segment of tubing B into first recess 24 to form said segment into flare 16. The tool D is now rotated one revolution relative to tubing B to form a circumferentially extending flare 16 on the tubing that extends into the first recess 24. The flare 16 so formed locks the ferrule C on one end ofa length of tubing B. After the flare 16 is formed as above described, the handle is rotated in a direction to increase the distance between spools 90 and the rollers 86 and 88 to permit the tool D to be separated from the tubing B.

lclaim:

l. A coupling for use in connecting two axially aligned lengths of tubing having first and second ends that are longitudinally spaced and on which first and second flares are formed, with each flare defining a circumferentially extending, interior, longitudinally curved first surface, said coupling including:

a. a resilient tubular connector of such configuration as to be capable of flexing at least longitudinally, said connector disposed between said first and second flares, and said connector having inwardly curved end extremities that contact said first surfaces to effect a primary seal therewith;

b. first and second ring-shaped ferrules mounted on said first and second ends of said tubing, said first and second ferrules having first and second circumferentially extending recesses therein, in which said first and second flares are disposed;

c. first and second resilient sealing rings disposed in said first and second recesses that sealingly contact said first and second flares, connector and first and second ferrules to provide secondary seals; and

d. first means for connecting said first and second ferrules one to the other to maintain said primary seal.

2. A coupling as defined in claim 1 in which said connector is of bellows configuration intermediate said end extremities thereof to permit said connector to flex both longitudinally and transversely, and said first means is a pliable elongate member formed into an endless loop that engages a plurality of circumferentially spaced slots formed in the exterior surfaces of said ferrules to define a succession of figure-8 configurations as said member extends around said bellows, and said member allowing said connector to flex transversely but preventing further longitudinal separation of said ferrules when said lengths of tubing are axially aligned.

3. A coupling as defined in claim 2 which in addition includes:

e. second means for preventing said elongate member being inadvertently displaced from slots.

4. A coupling as defined in claim 2 which in addition includes:

e. second means for maintaining substantially constant tension on said elongate member as said connector flexes.

5. A coupling as defined in claim 1 in which said first and second ferrules are in abutting contact and of such configuration as to cooperate with one another to define an interior annulus shaped confined space, and said connector including a circumferentially extending, outwardly projecting portion of generally U-shaped transverse cross section that extends into but does not completely fill said confined space, said portion being longitudinally deformed in a direction to maintain said curved extremities in pressure sealing contact with said first surfaces.

6. A coupling as defined in claim 5 in which said first means is a band of high tensile strength wire that extends around said first and second ferrules and removably engages a plurality of spaced slots formed in the exterior surfaces thereof.

7. A coupling as defined in claim 1 in which said first and second ferrules are in abutting contact and of such configuration as to cooperate with one another to define an interior annulus-shaped confined space, said connector including a circumferentially extending outwardly projecting portion that does not completely fill said space, with the transverse cross section of said outwardly projecting portion being in the form of a rectangular U that has an inwardly extending loop within the confines thereof, said outwardly extending portion being disposed in said confined space but not completely filling the same, and said outwardly projecting portion being longitudinally deformed in a direction to maintain said curved extremities in pressure sealing contact with said first surfaces.

8. A coupling as defined in claim 7 in which said first means is a band of high tensile strength wire that extends around said first and second ferrules and removably engages a pluralityof spaced slots formed in the exterior surfaces thereof.

9. A coupling for use in connecting two axially aligned longitudinally spaced lengths of tubing, said coupling including:

a. first and second ring-shaped ferrules secured to the adjacent end extremities of said lengths of tubing, said first and second ferrules in abutting contact with one another and of such configuration as to cooperate with one another to define an annulus shaped interior confined space that is in communication with the bores that extend longitudinally through said ferrules, and said first and second ferrules having circumferentially extending, in terior, longitudinally curved first surfaces within the interior thereof; a resilient tubular connector disposed within the confines of said first and second ferrules, said connector having inwardly curving end extremities that contact said first su rfaces, and said connector including an intermediately disposed outwardly projecting portion that extends into said confined space but does not completely fill the same, said outwardly projecting portion being longitudinally deformed in a direction to main said end extremities in pressure sealing contact with said first surfaces; and

c. first means for removably holding said first and second ferrules in said abutting contact.

10. A coupling as defined in claim 1 wherein said sealing ring is of transverse cross section that defines three spaced pressure-sealing lobes. 

1. A coupling for use in connecting two axially aligned lengths of tubing having first and second ends that are longitudinally spaced and on which first and second flares are formed, with each flare defining a circumferentially extending, interior, longitudinally curved first surface, said coupling including: a. a resilient tubular connector of such configuration as to be capable of flexing at least longitudinally, said connector disposed between said first and second flares, and said connector having inwardly curved end extremities that contact said first surfaces to effect a primary seal therewith; b. first and second ring-shaped ferrules mounted on said first and second ends of said tubing, said first and second ferrules having first and second circumferentially extending recesses therein, in which said first and second flares are disposed; c. first and second resilient sealing rings disposed in said first and second recesses that sealingly contact said first and second flares, connector and first and second ferrules to provide secondary seals; and d. first means for connecting said first and second ferrules one to the other to maintain said primary seal.
 2. A coupling as defined in claim 1 in which said connector is of bellows configuration intermediate said end extremities thereof to permit said connector to flex both longitudinally and transversely, and said first means is a pliable elongate member formed into an endless loop that engages a plurality of circumferentially spaced slots formed in the exterior surfaces of said ferrules to define a succession of figure-8 configurations as said member extends around said bellows, and said member allowIng said connector to flex transversely but preventing further longitudinal separation of said ferrules when said lengths of tubing are axially aligned.
 3. A coupling as defined in claim 2 which in addition includes: e. second means for preventing said elongate member being inadvertently displaced from slots.
 4. A coupling as defined in claim 2 which in addition includes: e. second means for maintaining substantially constant tension on said elongate member as said connector flexes.
 5. A coupling as defined in claim 1 in which said first and second ferrules are in abutting contact and of such configuration as to cooperate with one another to define an interior annulus shaped confined space, and said connector including a circumferentially extending, outwardly projecting portion of generally U-shaped transverse cross section that extends into but does not completely fill said confined space, said portion being longitudinally deformed in a direction to maintain said curved extremities in pressure sealing contact with said first surfaces.
 6. A coupling as defined in claim 5 in which said first means is a band of high tensile strength wire that extends around said first and second ferrules and removably engages a plurality of spaced slots formed in the exterior surfaces thereof.
 7. A coupling as defined in claim 1 in which said first and second ferrules are in abutting contact and of such configuration as to cooperate with one another to define an interior annulus-shaped confined space, said connector including a circumferentially extending outwardly projecting portion that does not completely fill said space, with the transverse cross section of said outwardly projecting portion being in the form of a rectangular U that has an inwardly extending loop within the confines thereof, said outwardly extending portion being disposed in said confined space but not completely filling the same, and said outwardly projecting portion being longitudinally deformed in a direction to maintain said curved extremities in pressure sealing contact with said first surfaces.
 8. A coupling as defined in claim 7 in which said first means is a band of high tensile strength wire that extends around said first and second ferrules and removably engages a plurality of spaced slots formed in the exterior surfaces thereof.
 9. A coupling for use in connecting two axially aligned longitudinally spaced lengths of tubing, said coupling including: a. first and second ring-shaped ferrules secured to the adjacent end extremities of said lengths of tubing, said first and second ferrules in abutting contact with one another and of such configuration as to cooperate with one another to define an annulus shaped interior confined space that is in communication with the bores that extend longitudinally through said ferrules, and said first and second ferrules having circumferentially extending, interior, longitudinally curved first surfaces within the interior thereof; b. a resilient tubular connector disposed within the confines of said first and second ferrules, said connector having inwardly curving end extremities that contact said first surfaces, and said connector including an intermediately disposed outwardly projecting portion that extends into said confined space but does not completely fill the same, said outwardly projecting portion being longitudinally deformed in a direction to main said end extremities in pressure sealing contact with said first surfaces; and c. first means for removably holding said first and second ferrules in said abutting contact.
 10. A coupling as defined in claim 1 wherein said sealing ring is of transverse cross section that defines three spaced pressure-sealing lobes. 